"Responsible adults" don't use MJ.
I pay my taxes, own my home, get up at 5:00AM every morning and go to work, and vote. And I smoke marijuana. If that's not responsible enough for you, I don't care.
Sure they do. But since they're responsible about it, you never hear about it.
Do "responsible adults" drink alcohol (a much more dangerous and physically addictive substance)?
Can't you people see your arguments are silly, bigoted, and inconsistent.
But "responsible adults" smoke cigarettes, drink alcohol, and down unknown quantities of "legal" drugs.